MEMS scanner

ABSTRACT

A MEMS scanner may include a first flexible arm extending substantially in a forward direction and a base connected to a proximal end of the first flexible arm, the base being thicker than the first flexible arm in a vertical direction. The MEMS scanner may further include a second flexible arm connected to a distal end of the first flexible arm, the second flexible arm extending substantially in a reverse direction. The MEMS scanner may further include a mirror coupled to a distal end of the second flexible arm. In one implementation, the MEMS scanner may be a non-resonant scanner.

BACKGROUND

Scanning mirrors are used in a wide variety of applications, such asdisplay systems, imaging systems, and LIDAR systems. In each system,light from a light source is scanned in one or more directions via acontrollable mirror or a set of controllable mirrors.

SUMMARY

A MEMS scanner is disclosed herein, which may include a first flexiblearm extending substantially in a forward direction and a base connectedto a proximal end of the first flexible arm, the base being thicker thanthe first flexible arm in a vertical direction. The MEMS scanner mayfurther include a second flexible arm connected to a distal end of thefirst flexible arm, the second flexible arm extending substantially in areverse direction. The MEMS scanner may further include a mirror coupledto a distal end of the second flexible arm.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a MEMS scanner according to a firstembodiment of the present disclosure.

FIG. 2 shows a top view of the MEMS scanner of FIG. 1.

FIG. 3A shows a side view of the MEMS scanner of FIG. 1 in an actuatedstate, and FIG. 3B shows a side view of the MEMS scanner of FIG. 1 in areverse actuated state.

FIG. 4 shows a top view of a MEMS scanner according to a secondembodiment of the present disclosure.

FIG. 5 shows a schematic view of an exemplary display system includingthe MEMS scanner of FIG. 1.

FIG. 6 shows a flowchart of a scanning method for a MEMS scanner.

DETAILED DESCRIPTION

In some scanning display systems, laser light is reflected by a mirrorassembly at different angles to project reflected laser light throughouta field-of-view (FOV). Other optical systems such as imaging systems andLIDAR systems may similarly utilize a mirror assembly to reflect laserlight. To achieve a range of reflection angles, the mirror assembly mayinclude one or more actuators to rotate one or more mirrors of themirror assembly. Various types of scanning mirrors may be used,including microelectromechanical system (MEMS) mirrors.

One or more mirrors of a MEMS mirror assembly may be rotated about anaxis in horizontal and/or vertical directions to produce viewable imagesin a FOV in a display system. In different examples, the mirror assemblymay include a single mirror driven in both horizontal and verticaldirections (2-dimensional, or 2D), or two mirrors separately driven inhorizontal and vertical directions (1-dimensional, or 1D). Differentscan rates may be employed in the horizontal and vertical directions. Ina two-mirror system, for example, a horizontal scanning mirror may bedriven at a relatively fast rate (e.g., ˜27 kHz), whereas a verticalscanning mirror may be driven at a relatively slower rate (e.g., ˜60Hz). The horizontal and vertical scan rates may at least partiallydetermine the resolution of images generated at these rates, along withother factors such as mirror aperture (e.g., diameter) and scan angle.

Non-resonant scanning mirrors are suitable for 1D rotation as a slowscanner. Piezoelectric actuators are commonly used in resonant scanningmirrors, but present difficulties when used in non-resonantapplications. When the piezoelectric material of the actuator isactuated, only slight motion is typically generated outside of aresonant frequency. With only slight motion, the scanning mirror willhave a very narrow displacement angle and implementing the scanningmirror in a display system, for example, would be difficult.

To address these issues, FIG. 1 shows a perspective view of a MEMSscanner 10 according to a first embodiment of the present disclosure.The MEMS scanner 10 may include a first flexible arm 12 extendingsubstantially in a forward direction, and a base 14 connected to aproximal end 12A of the first flexible arm 12. Here, the first flexiblearm 12 has a curved outer edge and a slightly curved inner edge suchthat it is wider at its proximal end 12A than at its distal end 12B, andextends substantially forward. The base 14 may be thicker than the firstflexible arm 12 in a vertical direction (denoted as “UP” and “DOWN” inFIG. 1) in order to provide a stable fulcrum for the proximal end 12A.The MEMS scanner 10 may include a second flexible arm 16 connected tothe distal end 12B of the first flexible arm 12, and the second flexiblearm 16 may extend substantially in a reverse direction (e.g., therearward direction which is the reverse of the forward direction in FIG.1). Here, the second flexible arm 16 has curved edges and a distal end16B thereof is curved inward, and the second flexible arm 16 extendssubstantially rearward. Finally, The MEMS scanner 10 may include amirror 18 coupled to the distal end 16B of the second flexible arm 16.While the mirror 18 is illustrated here as a rectangle, any suitableshape may be adopted.

FIG. 2 shows a top view of the MEMS scanner 10 of FIG. 1. Both FIGS. 1and 2 illustrate that the MEMS scanner 10 may include a thin film 20 ofa piezoelectric material on each of the first and second flexible arms12, 16. The piezoelectric material may be a ceramic material such aslead zirconate titanate (PZT), which may be doped to adjust itspiezoelectric constant. The thin films 20 may be formed by any suitablemethod, including chemical vapor deposition, electron beam evaporation,etc.

Other than the thin films 20, the main body of the MEMS scanner 10, suchas the arms 12, 16 and base 14, as well as the mirror 18, may be made ofsilicon. Each silicon piece may be formed integrally together by, forexample, reactive ion etching, sputtering, and/or other process(es). TheMEMS scanner 10 may be a non-resonant scanner, sometimes referred to as“linear,” and thus is not configured to vibrate at or near a singleresonant frequency.

The piezoelectric material in the thin film 20 may expand or contractaccording to a voltage applied thereto, causing motion in the flexiblearms 12, 16. Since each arm 12, 16 is wider at its proximal end 12A, 16Athan at its distal end 12B, 16B, the force pushing on the respective arm12, 16 from the actuated piezoelectric material may be stronger towardthe proximal end 12A, 16A compared to at its distal end 12B, 16B. Aseach proximal end 12A, 16A is adjacent the fulcrum of the bend, thistranslates into increased motion compared to having the same thicknessat each distal end 12B, 16B.

FIG. 2 illustrates various dimensions for one example of the MEMSscanner 10. Here, the MEMS scanner 10 may be less than 10 mm wide by 10mm long in total, and here, may be 9 mm wide by 7.3 mm long. The base 14is illustrated as a U-shaped block, with the first flexible arm 12attached at the top of one end of the U-shape. The length of the middlesection of the U-shape may be 1.25 mm. The first flexible arm 12 may bewider than the second flexible arm 16. For example, the widest point ofthe first flexible arm 12, located adjacent the base 14, may be 1.9 mm.By contrast, the second flexible arm 16 may range in this example from0.2 mm at its narrowest to 0.7 mm at its widest. The mirror 18 supportedby the second flexible arm 16 may be 3 mm wide by 2 mm long. The secondflexible arm 16 may be made smaller than the first flexible arm 12 dueto the mass of the mirror 18 needed to be moved when the second flexiblearm 16 moves. A thickness of the first flexible arm 12 may be 20-60 μm,and here, may be 40 μm (see FIG. 3). Further, a thickness of the secondflexible arm 16 may be the same.

While a single first flexible arm 12 and a single second flexible arm 16have been described thus far, the first flexible arm 12 may be one of apair of first flexible arms 12, and the second flexible arm 16 may beone of a pair of second flexible arms 16. The MEMS scanner 10 may besubstantially symmetric on its left and right sides, which may provideadditional control for limiting motion to one desired dimension.Alternatively, the MEMS scanner 10 may be asymmetric, as in a secondembodiment described with reference to FIG. 4.

A first arch 22A may be formed by the pair of first flexible arms 12 anda first support bar 24 connecting the distal ends 12B thereof.Similarly, a second arch 22B may be formed by the pair of secondflexible arms 16 and a second support bar 26 connecting distal ends 16Bthereof, and the second flexible arms 16 may be connected to the mirror18 via the second support bar 26. The second arch 22B may be nestedinside the first arch 22A and arranged in a reverse orientation relativeto the first arch 22A. In this manner, the first arch 22A formed by thepair of first flexible arms 12 may be configured to pivot where it isanchored at the base 14 in the form of a living hinge, and the secondarch 22B formed by the pair of second flexible arms 16 may be configuredto pivot where it is anchored at the first arch 22A in the form of aliving hinge. Each of the support bars 24, 26 may stabilize therespective arms 12, 16 when bending upward or downward, and suppressmovement in a second dimension such as twisting to the side.

FIG. 3A shows a side view of the MEMS scanner of FIG. 1 in an actuatedstate, and FIG. 3B shows a side view of the MEMS scanner of FIG. 1 in areverse actuated state. The displacement of the arms 12, 16 isexaggerated for illustration. Rather, a maximum angular displacement(mechanical) of the mirror 18 is 12°, which is the total of the anglesθ₁ and θ₂. In addition, while the arms 12, 16 are illustrated asextending linearly from a bent point during actuation for simplicity, inactuality, some curvature is generally present during actuation.

After the thin films 20 of the first flexible arms 12 are actuated witha positive voltage, the piezoelectric material of the thin films 20expands and bends the first flexible arms 12 downward from the proximalends 12B which are held in place by the substantially larger base 14(see FIG. 3A). Because the proximal ends 16A of the second flexible arms16 are attached to the distal ends 12B of the first flexible arms 12,when the distal ends 12B move further downward than any other part ofthe first flexible arms 12, the proximal ends 16A of the second flexiblearms 16 are brought downward and the distal ends 16B tilt upwardcompared to the flat state of FIGS. 1 and 2. In addition, if the thinfilms 20 of the second flexible arms 16 are actuated by a negativevoltage, the second flexible arms 16 will bend in the opposite directionof the first flexible arms 12 at their proximal ends 16A, lifting theirdistal ends 16A further upward. This double leverage configuration mayincrease the angular displacement of the mirror 18 held by the secondsupport bar 26 (see FIGS. 1-2) between the second flexible arms 16compared to a configuration with only one pivot point. Accordingly, thetypically low mobility of piezoelectric actuators outside of a resonantfrequency may be compensated without introducing unwanted twisting.

In FIG. 3B, the polarity of the voltages is reversed, so that a negativevoltage is applied to the first flexible arms 12, causing them to riseupward, and a positive voltage is applied to the second flexible arms16, causing them to bend downward. The downward displacement of thesecond flexible arms 16 in FIG. 3B as well as of the first flexible arms12 in FIB. 3A is limited by the vertical thickness of the base 14.Accordingly, the base 14 may be set to be as thick as the maximumdesired negative displacement of the arms 12, 16, and may differ fromthe thickness illustrated in the drawings.

FIG. 4 shows a top view of a MEMS scanner 110 according to a secondembodiment of the present disclosure. As briefly discussed above, ratherthan the symmetric configuration of the MEMS scanner 10, the MEMSscanner 110 may be asymmetric. Accordingly, the MEMS scanner 110 mayinclude only one first flexible arm 112 and only one second flexible arm116, both of which curve after a straight extending portion, toaccommodate a mirror 118 between the arms 112, 116. Compared to the MEMSscanner 10, the MEMS scanner 110 with single arms 112, 116 mayexperience increased twisting. To reduce twisting somewhat, thin films120 may be placed only on the substantially straight portions, andvarious portions of the MEMS scanner 110 may be weighted differently.

FIG. 5 shows a schematic view of an exemplary display system 500including the MEMS scanner 10 of FIG. 1. The display system 500 may beused in conjunction with, or incorporated in, a computing device such asa tablet, smartphone, laptop computer, desktop computer, or head-mounteddisplay, for example. An image or video source 502 may be captured by acamera, rendered by a processor running a program to create the video tobe displayed, or stored in memory, for example. A controller 504 such asa processor with associated memory may be configured to direct one ormore light sources 506, based on the video source 502, to a MEMSscanning mirror assembly 508. The MEMS scanning mirror assembly 508 maycomprise a slow scanner 510 configured to scan in a first direction, anda fast scanner 512 configured to scan in a second directionperpendicular to the first direction. The slow scanner 510 may be avertical scanning mirror, and the fast scanner 512 may be a horizontalscanning mirror. The slow scanner 510 may be the MEMS scanner 10 or 110,for example. The fast scanner 512 may be a resonant scanner, forexample.

In addition, the controller 504 may be configured to control actuators514A, 514B of each of the scanners 510, 512. The actuators 514A mayinclude the piezoelectric thin films 20 of the MEMS scanner 10 or 110,for example. Further, the actuators 514A may include a voltage sourcecontrollable by the controller 504 to apply a voltage to thepiezoelectric thin films 20. The voltage may be applied as a rampsignal, for example. On the other hand, the actuators 514B may be of anysuitable type for a fast scanner, which may include piezoelectricactuators, bimetallic strips, magnetic actuators, electrostaticactuators, and/or movable masses. Finally, the light reflected by thescanners 510, 512 of the MEMS scanning mirror assembly 508 may be output516 on a display screen, for example, to display the video.

FIG. 6 shows a flowchart of a scanning method 600 for a MEMS scanner.The following description of method 600 is provided with reference tothe MEMS scanner 10 described above and shown in FIGS. 1-3B. It will beappreciated that method 600 may also be performed in other contextsusing other suitable components.

With reference to FIG. 6, at 602, the method 600 may include forming afirst flexible arm to extend substantially in a forward direction. At604, a base may be connected to a proximal end of the first flexiblearm, and at 606, the base may be thicker than the first flexible arm ina vertical direction. As discussed above, a thick base may provide astable support for the first flexible arm. In contrast, a thickness ofthe first flexible arm may be 20-60 μm, and may be 40 μm in someembodiments. At 608, the method 600 may include forming a secondflexible arm connected to a distal end of the first flexible arm, thesecond flexible arm extending substantially in a reverse direction ofthe forward direction. The first flexible arm may be wider than thesecond flexible arm, which may allow the second flexible arm to movewhile supporting other components having considerable mass.

In some cases, the first flexible arm may be one of a pair of firstflexible arms, and the second flexible arm may be one of a pair ofsecond flexible arms. In such a case, at 610, the method 600 may includeforming a first arch by the pair of first flexible arms and a firstsupport bar connecting the distal ends thereof. At 612, the method 600may include forming a second arch by the pair of second flexible armsand a second support bar connecting the distal ends thereof. At 614, thesecond flexible arms may be connected to the mirror via the secondsupport bar. In this manner, the nested arches discussed above may beformed.

At 616, the method 600 may include applying a voltage to actuate a thinfilm of a piezoelectric material on each of the first and secondflexible arms. The voltage may be controlled by a controller, asdiscussed above. As a result of applying the voltage, at 618, the method600 may include bending the first flexible arm to displace the distalend thereof, and at 620, the method 600 may include bending the secondflexible arm to displace a distal end thereof, the bending of the secondflexible arm being in a direction opposite to the bending of the firstflexible arm. Adjusting the voltage applied to each arm may adjust thedirection (e.g., up or down) and magnitude of the bending. As a resultof the bending of the arms, at 622, the method 600 may includedisplacing a mirror connected to the second flexible arm. The MEMSscanner may be a non-resonant scanner, and may be configured to scanalong one axis using the mirror displaced at varying angles. A maximumangular displacement (mechanical) of the mirror may be 12°.

In some embodiments, devices described herein may be tied to a computingsystem of one or more computing devices. Such computing devices may takethe form of one or more personal computers, server computers, tabletcomputers, home-entertainment computers, network computing devices,gaming devices, mobile computing devices, mobile communication devices(e.g., smart phone), and/or other computing devices, and wearablecomputing devices such as smart wristwatches and head mounted augmentedreality devices. One such computing device is the controller 504 whichcontrols the MEMS scanner 10 or 110, and the computing device used inconjunction with, or incorporating, the display system 500.

The computing device may include a logic processor, volatile memory, anda non-volatile storage device. The logic processor includes one or morephysical devices configured to execute instructions. For example, thelogic processor may be configured to execute instructions that are partof one or more applications, programs, routines, libraries, objects,components, data structures, or other logical constructs. Suchinstructions may be implemented to perform a task, implement a datatype, transform the state of one or more components, achieve a technicaleffect, or otherwise arrive at a desired result.

The logic processor may include one or more physical processors(hardware) configured to execute software instructions. Additionally oralternatively, the logic processor may include one or more hardwarelogic circuits or firmware devices configured to executehardware-implemented logic or firmware instructions. Processors of thelogic processor may be single-core or multi-core, and the instructionsexecuted thereon may be configured for sequential, parallel, and/ordistributed processing. Individual components of the logic processoroptionally may be distributed among two or more separate devices, whichmay be remotely located and/or configured for coordinated processing.Aspects of the logic processor may be virtualized and executed byremotely accessible, networked computing devices configured in acloud-computing configuration. In such a case, these virtualized aspectsare run on different physical logic processors of various differentmachines, it will be understood.

The non-volatile storage device may include one or more physical devicesconfigured to hold instructions executable by the logic processors toimplement portions of the methods and processes described herein. Whensuch methods and processes are implemented, the state of non-volatilestorage device may be transformed—e.g., to hold different data.

The non-volatile storage device may include physical devices that areremovable and/or built-in. Non-volatile storage device?06 may includeoptical memory (e.g., CD, DVD, HD-DVD, Blu-Ray Disc, etc.),semiconductor memory (e.g., ROM, EPROM, EEPROM, FLASH memory, etc.),and/or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tapedrive, MRAM, etc.), or other mass storage device technology. Thenon-volatile storage device may include nonvolatile, dynamic, static,read/write, read-only, sequential-access, location-addressable,file-addressable, and/or content-addressable devices. It will beappreciated that the non-volatile storage device is configured to holdinstructions even when power is cut to the non-volatile storage device.

The volatile memory may include physical devices that include randomaccess memory. The volatile memory is typically utilized by the logicprocessor to temporarily store information during processing of softwareinstructions. It will be appreciated that the volatile memory typicallydoes not continue to store instructions when power is cut to thevolatile memory.

Aspects of the logic processor, the volatile memory, and thenon-volatile storage device may be integrated together into one or morehardware-logic components. Such hardware-logic components may includefield-programmable gate arrays (FPGAs), program- andapplication-specific integrated circuits (PASIC/ASICs), program- andapplication-specific standard products (PSSP/ASSPs), system-on-a-chip(SOC), and complex programmable logic devices (CPLDs), for example.

The following paragraphs provide additional support for the claims ofthe subject application. One aspect provides A MEMS scanner comprising afirst flexible arm extending substantially in a forward direction, abase connected to a proximal end of the first flexible arm, the basebeing thicker than the first flexible arm in a vertical direction, asecond flexible arm connected to a distal end of the first flexible arm,the second flexible arm extending substantially in a reverse direction,and a mirror coupled to a distal end of the second flexible arm. In thisaspect, additionally or alternatively, the MEMS scanner may be anon-resonant scanner. In this aspect, additionally or alternatively, theMEMS scanner may further comprise a thin film of a piezoelectricmaterial on each of the first and second flexible arms. In this aspect,additionally or alternatively, the first flexible arm may be wider thanthe second flexible arm. In this aspect, additionally or alternatively,the first flexible arm may be one of a pair of first flexible arms, andthe second flexible arm may be one of a pair of second flexible arms. Inthis aspect, additionally or alternatively, a first arch may be formedby the pair of first flexible arms and a first support bar connectingthe distal ends thereof. In this aspect, additionally or alternatively,a second arch may be formed by the pair of second flexible arms and asecond support bar connecting distal ends thereof, and the secondflexible arms may be connected to the mirror via the second support bar.In this aspect, additionally or alternatively, the MEMS scanner may beless than 10 mm wide by 10 mm long. In this aspect, additionally oralternatively, a thickness of the first flexible arm may be 40 μm. Inthis aspect, additionally or alternatively, a maximum angulardisplacement of the mirror may be 12°.

Another aspect provides a scanning method for a MEMS scanner. The methodmay comprise forming a first flexible arm to extend substantially in aforward direction, wherein a base is connected to a proximal end of thefirst flexible arm, the base being thicker than the first flexible armin a vertical direction, forming a second flexible arm connected to adistal end of the first flexible arm, the second flexible arm extendingsubstantially in a reverse direction of the forward direction, bendingthe first flexible arm to displace the distal end thereof, bending thesecond flexible arm to displace a distal end thereof, wherein thebending of the second flexible arm is in a direction opposite to thebending of the first flexible arm, and displacing a mirror connected tothe second flexible arm. In this aspect, additionally or alternatively,the MEMS scanner may be a non-resonant scanner. In this aspect,additionally or alternatively, the method may further comprise applyinga voltage to actuate a thin film of a piezoelectric material on each ofthe first and second flexible arms. In this aspect, additionally oralternatively, the first flexible arm may be wider than the secondflexible arm. In this aspect, additionally or alternatively, the firstflexible arm may be one of a pair of first flexible arms, and the secondflexible arm may be one of a pair of second flexible arms. In thisaspect, additionally or alternatively, the method may further compriseforming a first arch by the pair of first flexible arms and a firstsupport bar connecting the distal ends thereof. In this aspect,additionally or alternatively, the method may further comprise forming asecond arch by the pair of second flexible arms and a second support barconnecting the distal ends thereof. The second flexible arms may beconnected to the mirror via the second support bar. In this aspect,additionally or alternatively, a thickness of the first flexible arm maybe 40 μm. In this aspect, additionally or alternatively, a maximumangular displacement of the mirror may be 12°.

Another aspect provides a MEMS scanning mirror assembly comprising aslow scanner configured to scan in a first direction. The slow scannermay comprise a first flexible arm extending substantially in a forwarddirection, a base connected to a proximal end of the first flexible arm,the base being thicker than the first flexible arm, a second flexiblearm connected to a distal end of the first flexible arm, the secondflexible arm extending substantially in a reverse direction, and amirror connected to the second flexible arm. The MEMS scanning mirrorassembly may further comprise a fast scanner configured to scan in asecond direction perpendicular to the first direction.

It will be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. As such, various acts illustrated and/ordescribed may be performed in the sequence illustrated and/or described,in other sequences, in parallel, or omitted. Likewise, the order of theabove-described processes may be changed.

The subject matter of the present disclosure includes all novel andnon-obvious combinations and sub-combinations of the various processes,systems and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

The invention claimed is:
 1. A MEMS scanner comprising: a pair of firstflexible arms each extending substantially in a forward direction from aproximal end thereof to a distal end thereof, each of the first flexiblearms gradually tapering from a width at the proximal end thereof to anarrower width at the distal end thereof; a base connected to theproximal ends of the pair of first flexible arms, the base being thickerthan each of the first flexible arms in a vertical direction; a pair ofsecond flexible arms connected to the respective distal ends of the pairof first flexible arms, the pair of second flexible arms extendingsubstantially in a reverse direction of the forward direction from aproximal end thereof to a distal end thereof, the reverse direction andthe forward direction being substantially orthogonal to the verticaldirection, each of the pair of second flexible arms gradually taperingfrom a width at the proximal end thereof to a narrower width at thedistal end thereof; and a mirror coupled to the distal ends of the pairof second flexible arms, wherein a first arch is formed by the pair offirst flexible arms and a first support bar connecting the distal endsthereof, a second arch is formed by the pair of second flexible arms anda second support bar connecting distal ends thereof, and the secondflexible arms are connected to the mirror via the second support bar. 2.The MEMS scanner of claim 1, wherein the MEMS scanner is a non-resonantscanner.
 3. The MEMS scanner of claim 1, further comprising a thin filmof a piezoelectric material on each of the pairs of first and secondflexible arms.
 4. The MEMS scanner of claim 1, wherein each firstflexible arm is wider than each second flexible arm.
 5. The MEMS scannerof claim 1, wherein the MEMS scanner is less than 10 mm wide by 10 mmlong.
 6. The MEMS scanner of claim 1, wherein a thickness of the pair offirst flexible arms is 40 μm.
 7. The MEMS scanner of claim 1, wherein amaximum mechanical angular displacement of the mirror is 12°.
 8. Ascanning method for a MEMS scanner, the method comprising: forming apair of first flexible arms to each extend substantially in a forwarddirection from a proximal end thereof to a distal end thereof, each ofthe first flexible arms gradually tapering from a width at the proximalend thereof to a narrower width at the distal end thereof, forming abase connected to the proximal ends of the pair of first flexible arms,the base being thicker than each of the first flexible arms in avertical direction; forming a pair of second flexible arms connected tothe respective distal ends of the pair of first flexible arms, the pairof second flexible arms each extending substantially in a reversedirection of the forward direction from a proximal end thereof to adistal end thereof, the reverse direction and the forward directionbeing substantially orthogonal to the vertical direction, wherein eachof the first flexible arms gradually taper from a width at the proximalend thereof to a narrower width at the distal end thereof; forming afirst arch by the pair of first flexible arms and a first support barconnecting the distal ends thereof; forming a second arch by the pair ofsecond flexible arms and a second support bar connecting distal endsthereof; bending the pair of first flexible arms to displace the distalends thereof; bending the pair of second flexible arms to displace thedistal ends thereof, wherein the bending of the pair of second flexiblearms is in a direction opposite to the bending of the pair of firstflexible arms; and displacing a mirror connected to the pair of secondflexible arms via the second support bar.
 9. The scanning method ofclaim 8, wherein the MEMS scanner is a non-resonant scanner.
 10. Thescanning method of claim 8, further comprising applying a voltage toactuate a thin film of a piezoelectric material on each of the pair offirst and second flexible arms.
 11. The scanning method of claim 8,wherein each first flexible arm is wider than each second flexible arm.12. The scanning method of claim 8, wherein a thickness of the pair offirst flexible arms is 40 μm.
 13. The scanning method of claim 8,wherein a maximum mechanical angular displacement of the mirror is 12°.14. A MEMS scanning mirror assembly comprising: a slow scannerconfigured to scan in a first direction, comprising: a pair of firstflexible arms extending substantially in a forward direction from aproximal end thereof to a distal end thereof, each of the first flexiblearms gradually tapering from a width at the proximal end thereof to anarrower width at the distal end thereof; a base connected to theproximal ends of the pair of first flexible arms, the base being thickerthan each of the first flexible arms; a pair of second flexible armsconnected to the respective distal ends of the pair of first flexiblearms, the pair of second flexible arms extending substantially in areverse direction of the forward direction from a proximal end thereofto a distal end thereof, the reverse direction and the forward directionbeing substantially orthogonal to the vertical direction, each of thepair of second flexible arms gradually tapering from a width at theproximal end thereof to a narrower width at the distal end thereof; anda mirror connected to the pair of second flexible arms; and a fastscanner configured to scan in a second direction perpendicular to thefirst direction, wherein a first arch is formed by the pair of firstflexible arms and a first support bar connecting the distal endsthereof, a second arch is formed by the pair of second flexible arms anda second support bar connecting distal ends thereof, and the secondflexible arms are connected to the mirror via the second support bar.